How to delegate a touch event to an entity when the entity has a component where the SKSpriteNode was defined, and the spritenode is underneeth another node based on z-index

BaseScene.swift

//  BaseScene.swift
//  Hospital Demo
//
//  Created by Ben Hutton on 17/11/2015.
//  Copyright © 2015 Ben Hutton. All rights reserved.
//

import Foundation
import SpriteKit
import GameplayKit
import HLSpriteKit

class BaseScene: HLScene {
...
...

  override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    print("touched!")

    let touch = touches.first!
    let positionInScene = touch.locationInNode(self)
    let touchedNodes = self.nodesAtPoint(positionInScene)

    for node in touchedNodes {
      print(node.userData)
      if((node.userData?["entity"]) != nil){
        let entity = node.userData!["entity"] as! GKEntity
        entity.componentForClass(TouchableSpriteComponent)?.callFunction()
      }
    }


  }


}

SpriteComponent.swift

//
//  SpriteComponent.swift
//  Hospital Demo
//
//  Created by Ben Hutton on 19/12/2015.
//  Copyright © 2015 Ben Hutton. All rights reserved.
//

import GameplayKit
import SpriteKit

class SpriteComponent: GKComponent {

  let node: SKSpriteNode

  init(texture: SKTexture) {
    node = SKSpriteNode(texture: texture, color: SKColor.whiteColor(), size: texture.size())
  }

  func addToNodeKey() {
    self.node.userData = NSMutableDictionary()
    self.node.userData?.setObject(self.entity!, forKey: "entity")
  }
  
}

Tile.swift

//
//  Tile.swift
//  Hospital Demo
//
//  Created by Ben Hutton on 19/12/2015.
//  Copyright © 2015 Ben Hutton. All rights reserved.
//

import SpriteKit
import GameplayKit

class Tile: GKEntity {

  init(imageName: String, x: Int, y: Int) {
    super.init()

    let spriteComponent = SpriteComponent(texture: SKTexture(imageNamed: imageName))
    addComponent(spriteComponent)
    spriteComponent.addToNodeKey()

    let width = Int((spriteComponent.node.texture?.size().width)!)
    let x = width * x + width / 2
    let y = width * y + width / 2

    let positionComponent = PositionComponent(x: x, y: y)

    addComponent(positionComponent)
    
    spriteComponent.node.position = CGPoint(x: x, y: y)
    
    let touchableComponent = TouchableSpriteComponent(){
      print("function of spritecomponent?")
      self.handleTouch()
      
    }
    addComponent(touchableComponent)
    
    let spriteDebugComponent = SpriteDebugComponent(node: spriteComponent.node)
    addComponent(spriteDebugComponent)

  }
  
  func handleTouch() {
    print("I am a TILE!")
    print(self.componentForClass(PositionComponent)?.x)
    print(self.componentForClass(PositionComponent)?.y)
    // Do some more things like change state of another component
  }
}

TouchableSpriteComponent.swift

//
//  TouchableSpriteComponent.swift
//  Hospital Demo
//
//  Created by Ben Hutton on 19/12/2015.
//  Copyright © 2015 Ben Hutton. All rights reserved.
//

import GameplayKit
import SpriteKit

class TouchableSpriteComponent: GKComponent {
  
  var entityTouched: ()->Void;
  
  init(f:() -> Void) {
    self.entityTouched = f
  }
  
  func callFunction() {
    self.entityTouched()
  }
  
}

Suggested improvments from irc: http://imgur.com/S2gzT16